[tex]P=\frac{a*h}{2} \\[/tex]
a-długość podstawy
h-wysokość
[tex]a)\\I.\\P=\frac{28cm*19cm}{2} \frac{532cm^2}{2} =266cm^2\\\\II.\\P=\frac{3,2dm*38cm}{2} =\frac{3,2dm*3,8dm}{2} =\frac{12,16dm^2}{2}=6,08dm^2\\\\III.\\P=\frac{7dm*6dm}{2}=\frac{42dm^2}{2}=21dm^2[/tex]
[tex]b)\\I.\\P=\frac{20cm*25cm}{2} =\frac{500cm^2}{2}=250cm^2\\ \\II.\\P=\frac{10m*3m}{2}=\frac{30m^2}{2} =15m^2\\\\III.\\P=\frac{32cm*24cm}{2}=\frac{768cm^2}{2} =384cm^2[/tex]
